CVE-2026-71889— PKIXCertPathReviewer X.509名称约束绕过漏洞
一分钟漏洞结论
影响对象
Legion of the Bouncy Castle Inc. BC-JAVA
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
在 Bouncy Castle for Java 1.86 版本之前的产品中，PKIXCertPathReviewer 的两个副本（即 和传统的 ）均未对终Entity 证书（end-entity certificate，即叶证书）应用 X.509 名称约束（Name Constraints）。 具体问题在于： 方法在遍历证书链时，使用了循环索引大于零的上界。这一设置符合仅由证书颁发机构（CA）证书执行步骤的要求，但在标准的证书路径（CertPath）顺序中，索引为零对应的是目标证书（即叶证书）。因此，RFC 52
可能的 ATT&CK 技术 1 AI
T1557 · Adversary-in-the-Middle
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一、 漏洞 CVE-2026-71889 基础信息
漏洞信息
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Vulnerability Title
PKIXCertPathReviewer does not apply X.509 name constraints to the target certificate
来源: CVE Program / CVE List V5
Vulnerability Description
In Bouncy Castle for Java before 1.86, neither copy of PKIXCertPathReviewer - org.bouncycastle.pkix.jcajce.PKIXCertPathReviewer nor the legacy org.bouncycastle.x509.PKIXCertPathReviewer - applied X.509 name constraints to the end-entity certificate. checkNameConstraints walked the path with a loop bound of index greater than zero, which is the bound the CA-only steps require, but index zero is the target certificate under the standard CertPath ordering, so the permitted and excluded subtree checks of RFC 5280 sec. 6.1.3 (b) and (c) never ran against the leaf's subject DN or its subjectAltName. A chain whose leaf violated a NameConstraints extension imposed by its own issuing CA therefore reported isValidCertPath() true with an empty error list, while CertPathValidator.getInstance("PKIX", "BC"), which shares no code with the reviewer, rejected the identical chain against the identical trust anchor. An application using the reviewer to make the trust decision rather than for diagnostics alongside a real validation accepted a certificate the constrained CA was never authorised to issue. Both copies now check every certificate in the path including the target, waive the sec. 4.2.1.10 self-issued exemption for the final certificate as sec. 6.1.3 requires, and skip the sec. 6.1.4 (g) constraint-accumulation step for the target. This issue also affects Bouncy Castle for Java LTS before 2.73.13, which carries only the org.bouncycastle.pkix.jcajce copy of the reviewer. It also affects Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).
来源: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
来源: CVE Program / CVE List V5
Vulnerability Type
证书验证不恰当
来源: CVE Program / CVE List V5
受影响产品
| 厂商 | 产品 | 影响版本 | CPE | 订阅 |
|---|---|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 ~ 1.86 | - |
|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 ~ 1.86 | - |
|
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 ~ 2.73.13 | - |
|
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.4 ~ 1.0.13 | - |
|
二、漏洞 CVE-2026-71889 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2026-71889 其他参考 (2)
同批安全公告 · Legion of the Bouncy Castle Inc. · 2026-10-03 · 共 12 条
| CVE-2026-71885 | 9.2 CRITICAL | MLS X.509凭证未绑定到LeafNode签名密钥 |
| CVE-2026-71888 | 8.7 HIGH | CMS 认证数据暴露攻击者插入的authAttrs |
| CVE-2026-71890 | 8.7 HIGH | MLS外部提交可移除任意组成员漏洞 |
| CVE-2026-85515 | 8.2 HIGH | OpenPGP消息截断未报告，绕过SEIPDv1完整性检查 |
| CVE-2026-71887 | 8.2 HIGH | OpenPGP 签名子键无交叉认证漏洞 |
| CVE-2026-71883 | 8.2 HIGH | Native AES密文解析器泄露原始AES密钥 |
| CVE-2026-71886 | 8.2 HIGH | OpenPGP 子键无证书认证漏洞 |
| CVE-2026-71891 | 7.1 HIGH | BLS12-381 密钥验证接受基于外部曲线的公钥 |
| CVE-2026-71892 | 6.9 MEDIUM | RFC 9709 HKDF派生密钥未执行CMS密钥传输接收方密钥大小验证 |
| CVE-2026-18040 | 5.9 MEDIUM | HQC 通过秘密索引表和采样器泄露私钥信息 |
| CVE-2026-97873 | 5.3 MEDIUM | JCA原始提供程序未限制PBES1和PKCS#12迭代次数 |
IV. Related Vulnerabilities
V. Comments for CVE-2026-71889
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